Array bounds and validation functions

These functions inspect arrays and validate values at runtime.

Array bounds

Function	Parameters	Returns
`LOWER_BOUND`	`ARR : ARRAY`, `DIM : ANY_INT`	`ANY_INT`
`UPPER_BOUND`	`ARR : ARRAY`, `DIM : ANY_INT`	`ANY_INT`

DIM is the 1-based dimension number. These are especially useful with conformant arrays (ARRAY[*]), where the bounds are not known until runtime — see derived types.

LOWER_BOUND(ARR : ARRAY, DIM : ANY_INT) : ANY_INT
UPPER_BOUND(ARR : ARRAY, DIM : ANY_INT) : ANY_INT

FOR i := LOWER_BOUND(data, 1) TO UPPER_BOUND(data, 1) DO
    sum := sum + data[i];
END_FOR;

Validation

Function	Parameters	Returns
`IS_VALID`	`IN : ANY_REAL`	`BOOL`
`IS_VALID_BCD`	`IN : ANY_BIT`	`BOOL`

IS_VALID returns FALSE for NaN/infinite floating-point values; IS_VALID_BCD checks that a bit string holds a valid BCD-encoded value.

IS_VALID(IN : ANY_REAL) : BOOL
IS_VALID_BCD(IN : ANY_BIT) : BOOL

IF IS_VALID(measurement) THEN
    average := (average + measurement) / 2.0;   // skip NaN/Inf readings
END_IF

IF IS_VALID_BCD(thumbwheel) THEN
    value := BYTE_BCD_TO_INT(thumbwheel);
END_IF